The present invention relates to a magnet warning device for a camera equipped with a focal plane electric shutter.
In cameras having a focal plane electric shutter, exposure is initiated by releasing the front shutter or front blind from its mechanically retained blocking porition to an unblocking position. The rear shutter or rear blind is retained in its unblocking position by a rear blind retaining electromagnet. A time constant circuit deenrgizes said electromagnet several predetermined seconds or fractions of a second after the starting operation of the front blind to release the rear blind from its retained condition and permit it to run to its blocking condition, thereby to ensure the desired exposure. However, if a malfunction is experienced, e.g., the magnet is not energized or the voltage necessary for retaining the rear blind is insufficient, the rear blind goes out of control and starts its running operation simultaneously with the start of the front blind. As a result there will be no exposure and proper photography becomes impossible. It therefore is important to provide the operator with some warning indication.
Several warning methods and devices are known in the art. The construction employed in such warning methods are, however, accompanied by a variety of drawbacks, such as, complexity, too many parts, too many steps of their assembly, inferiority in their production or instability in their function.